mckruz ComfyUI Troubleshooter
Diagnoses and resolves ComfyUI issues across four categories: server errors, workflow errors, quality issues, and performance problems.
Diagnosis Process
Step 1: Classify the Error
| Category | Symptoms | First Check |
|---|---|---|
| Server | Connection refused, timeouts, crashes | Is ComfyUI running? Check /system_stats |
| Workflow | Node errors, missing inputs, type mismatches | Validate workflow against inventory |
| Quality | Artifacts, wrong identity, blurry output | Check settings (CFG, weights, resolution) |
| Performance | OOM, slow generation, VRAM errors | Check VRAM usage, model sizes |
Step 2: Gather Context
Collect before diagnosing:
- Error message (exact text)
- Workflow being executed (or description)
- Models involved (checkpoint, LoRA, ControlNet, etc.)
- Settings (CFG, steps, resolution, sampler)
- Hardware (from
foundation/hardware-profile.md) - Inventory (from
state/inventory.json)
Step 3: Match Error Pattern
See references/troubleshooting.md for the full error database.
Quick Fix Reference
Top 10 Most Common Errors
1. "CUDA out of memory"
→ Use FP8: --fp8_e4m3fn-unet
→ Enable tiled VAE
→ Reduce resolution
→ Restart ComfyUI (clears fragmentation)
2. "Node type not found: {name}"
→ Install the custom node package via ComfyUI-Manager
→ Check comfyui-inventory node-to-package mapping
3. "Expected scalar type BFloat16 but found Float"
→ Precision mismatch. Add --force-fp16 or use matching precision nodes
4. Burned/overexposed faces → Lower CFG to 4-5 (InstantID) → Reduce identity method weight → Add noise to negative embeds (35%)
5. "No model found at path" → Check filename spelling (exact match required) → Verify file is in correct subdirectory → Run inventory scan to confirm
6. Watermark artifacts at 1024x1024 → Use 1016x1016 or 1020x1020 instead
7. Identity doesn't match reference → Use higher quality reference image (clear, front-facing) → Increase IP-Adapter weight to 0.8+ → Verify InsightFace antelopev2 is installed
8. Video flickering → Lower FaceDetailer denoise to 0.3 → Add deflicker post-processing → Increase AnimateDiff context overlap to 4+
9. Queue stuck/not processing
→ POST /interrupt to cancel
→ POST /free to unload models
→ Restart ComfyUI
10. Slow generation
→ Check if --lowvram is enabled (remove it on RTX 5090)
→ Use --highvram instead
→ Update cuDNN to 8800+
→ Enable SageAttention for Wan models
Decision Tree: Quality Issues
OUTPUT LOOKS WRONG
|
|-- Faces look wrong
| |-- Too smooth/plastic → Add skin texture LoRA (0.2-0.4)
| |-- Wrong identity → Increase identity weight, check reference quality
| |-- Burned/hot → Lower CFG to 4-5, reduce InstantID weight
| |-- Deformed → Add "bad anatomy, deformed" to negative
| |-- Different every time → Fix seed, add LoRA for consistency
|
|-- Colors wrong
| |-- Oversaturated → Lower CFG, add "oversaturated" to negative
| |-- Washed out → Check VAE is loaded, try different scheduler
| |-- Color shift in video → Add color correction post-processing
|
|-- Resolution/sharpness
| |-- Blurry → Increase steps (25-30), check resolution matches model
| |-- Pixelated → Use proper upscaler (4x-UltraSharp), not resize
| |-- Artifacts → Lower denoise, check for model corruption
|
|-- Composition
| |-- Ignoring prompt → Increase CFG slightly, simplify prompt
| |-- Extra limbs/objects → Add to negative prompt, use ControlNet
| |-- Wrong pose → Add ControlNet OpenPose with reference
Missing Dependency Resolution
When a workflow references something not in inventory:
Missing Custom Node
1. Identify package from class_type (see inventory skill's mapping)
2. Suggest: "Open ComfyUI-Manager → Search → Install {package_name}"
3. Alternative: "cd {ComfyUI}/custom_nodes && git clone {repo_url}"
4. Remind: Restart ComfyUI after installation
Missing Model
1. Look up in references/models.md for download link
2. Provide: exact filename, download URL, target directory
3. For large models (>10GB): suggest HF CLI for reliability
"huggingface-cli download {repo} {file} --local-dir {path}"
Version Incompatibility
1. Check ComfyUI version vs node package requirements
2. Suggest: "cd {ComfyUI} && git pull" for ComfyUI update
3. Or: pin specific node version if newest breaks things
Escalation
If troubleshooting doesn't resolve the issue:
- Check ComfyUI GitHub Issues for known bugs
- Check specific node package's Issues
- Search r/comfyui for community solutions
- Suggest posting in ComfyUI Discord with error details
Reference
references/troubleshooting.md- Full error database with solutionsstate/inventory.json- Current installation statereferences/models.md- Model download links and paths